1. Field of the Invention
The present invention relates to agricultural product tanks, and more particularly to support structure for supporting a plastic product tank on an implement frame.
2. Description of Related Art
Air seeders, sprayers and other similar types of implements typically include product tanks for bulk storage of material to be distributed by the implement onto or underneath the soil. These tanks have been fabricated by welding and/or bolting sheet metal panels in a tank configuration on an implement frame. Sheet metal construction is relatively expensive, primarily because a relatively long fabrication time is required to assemble the panels on the support frame. In addition, these metal tanks are relatively heavy and subject to water leakage and corrosion, particularly in tanks which are used to contain fertilizer.
As an alternative to metallic fabrication, the more recent past has seen a progression toward manufacture of such tanks from composites or plastics. These plastic tanks do not corrode as a result of the products transported within the tanks, overcome most of the water leakage problems attendant metallic construction, are less expensive to make and weigh less than tanks made from steel.
One of the challenges in using a plastic product tank is developing a structure that effectively supports the tank without creating what is essentially a plastic-lined steel hopper. Known vehicles carrying plastic product tanks typically use steel to support the plastic tanks, which presents two main problems: excessive cost compared to using an all-steel tank, and wear and chaffing at the plastic/steel intersecting surfaces. An all steel support structure which substantially eliminates wear requires that there not be any flat steel edges riding directly against the plastic. Therefore, all corners, edges and ends which would contact the plastic would require rounded surfaces, representing a substantial increase in fabrication and/or assembly cost.